1. Field of Invention
This invention relates generally to four wheel drive articulated tractors and, more particularly, to improvements to provide shielding for the drive line on articulated tractors having a drive line extending across the articulation joint.
2. Background of Prior Art
On articulated tractors of the type having a two opposing ends, typically an engine end supporting the engine providing operative power for the tractor and a cab end supporting the operator's cab and gearbox mechanism, joined by an articulation joint. Steering of the tractor is accomplished by manipulating the articulation joint with hydraulic actuators. In such tractors, the operative power for the tractor is delivered from the engine to the splitter gearbox on the opposing end of the tractor via a power input drive line extending from the engine end to the cab end across the articulation joint. For an example of such an articulated tractor, please review the New Holland Bidirectional.TM. Tractor TV 140.
It is desirable to cover this drive line with a shielding to prevent accidental engagement with the drive line. Such a shield, however, must cover the universal joint assembly of the drive line at the articulation joint throughout the entire range of movement of the articulation joint and the corresponding movement of the drive line. Furthermore, the universal joint will change length as the articulation joint is manipulated to effect steering of the tractor.
Likewise, the shield must be operable to cover the drive line as the universal joint changes length. U.S. Pat. No. 4,308,931 discloses a drive line shield that shields the drive line in the straight ahead position, but exposes the drive line when the articulated tractor is turning. It is of paramount importance that an individual be prevented from contacting the rotating drive line universal joints when the tractor is in all positions. Frequently servicing of various tractor components is accomplished when the articulated tractor is in a turned position.